The growth of high-quality materials is a fundamental foundation of condensed matter physics research, particularly the growth of high-quality single crystals. Single crystals have well-defined crystal structures and orientations, minimizing the effects of impurities, defects, and grain boundaries on physical properties. This enables more accurate investigations of the intrinsic electronic, magnetic, and lattice properties of materials.

At Brockman Hall at Rice University, we combine melting, vapor-phase, and solution-based methods to synthesis high-quality bulk single crystals, with annealing and doping performed when appropriate. Our methods include the floating-zone technique using a state-of-the-art, in-house-built high-pressure laser floating-zone furnace, the flux method using box furnaces, and vapor transport methods using tube furnaces.

We provide high-quality single crystals to numerous research groups for quantum materials research. If you are interested in collaboration, please contact us.

Basic physical property measurements are an essential part of the initial characterization of samples in condensed matter physics. Characterizing crystal structure, crystal orientation, and transport properties allows us to quickly assess material quality and fundamental physical properties, while providing a reliable foundation for further analysis and experiments.

For single-crystal structural characterization, we have a Laue diffraction system for rapidly determining the crystal orientation, symmetry, and quality of single-crystal samples, as well as for screening high-quality crystals suitable for subsequent experiments. For more precise and systematic structural analysis, we utilize the X-ray diffraction facilities at Rice University to perform both powder XRD and single-crystal XRD measurements. Powder XRD can be used for phase identification, lattice parameter analysis, and the detection of possible secondary phases. Single-crystal XRD provides more detailed information on the crystal structure, atomic positions, lattice parameters, site occupancies, and other structural parameters, providing an important basis for understanding the relationship between crystal structure and physical properties.

For transport measurements, we have a Physical Property Measurement System (PPMS) for temperature- and magnetic-field-dependent electrical and thermal transport measurements. By measuring the evolution of resistivity, thermal conductivity, and Seebeck coefficient/thermopower with temperature, magnetic field, and other external parameters, we can investigate metallic or insulating behavior, superconducting transitions, magnetic phase transitions, and other anomalous transport phenomena associated with electronic and phononic properties. For quantum materials with complex electronic correlations and magnetic behavior, these basic transport measurements provide important information for evaluating sample quality, determining transition temperatures, and further understanding their electronic and phononic properties.

Neutrons—with wavelengths and energies comparable to the length scales of interatomic spacings and lattice vibrations in solids—play a unique role in studying the microscopic structures and low-energy excitations of condensed matter. This is mainly due to the following characteristics:

1. Neutrons are scattered by atomic nuclei.
   As a result, light elements such as hydrogen and oxygen can produce strong neutron scattering, comparable to that from much heavier elements.

2. Neutrons are electrically neutral and possess a magnetic moment.
   This magnetic moment can interact with both localized magnetic ions and unpaired itinerant electrons in solids, making neutron scattering particularly well suited for investigating magnetic properties and spin degrees of freedom.

3. Neutrons are weakly interacting probes.
   The neutron scattering cross section is determined by the static and dynamic correlation functions of the system, without requiring corrections for significant perturbations introduced by the probe itself.

4. Neutrons have strong penetrating power and serve as a bulk probe.
   Therefore, neutron scattering is relatively insensitive to surface defects and can effectively probe the bulk properties of materials.

By measuring the changes in energy and momentum of neutrons scattered from a sample, we can obtain information about the static structure and dynamic response of materials under different conditions, such as temperature and magnetic field, thereby establishing connections between microscopic interactions and macroscopic physical properties. We conduct a wide range of neutron scattering experiments at neutron facilities in the United States, Japan, Australia, Switzerland, and other countries. Through neutron scattering, we investigate the structure and dynamics of quantum materials, including various low-energy collective phenomena.

As a leading neutron scattering research group, we continuously develop and apply new neutron scattering techniques. Our research methods can be broadly divided into elastic and inelastic neutron scattering. Elastic neutron scattering is primarily used to investigate magnetic structures, magnetic ordering, and crystal structures, as well as nanoscale structures through small-angle neutron scattering. Inelastic neutron scattering, on the other hand, probes a wide range of low-energy excitations by measuring the energy loss and momentum transfer of neutrons, including spin waves, magnetic excitations, phonons, and other collective modes. Depending on the research objectives, we employ different types of neutron spectrometers, including triple-axis spectrometers and time-of-flight spectrometers, to access a broad range of energy and momentum space.

Neutrons can interact with both atomic nuclei and electronic magnetic moments. Unpolarized neutron scattering uses a neutron beam without selecting a specific spin state and is relatively straightforward experimentally. Polarized neutron scattering, in contrast, controls and analyzes the spin states of the incident and scattered neutrons. By exploiting the interaction between neutron spin and magnetic moments in the material, it can distinguish nuclear from magnetic scattering and further resolve magnetic and nuclear structures, magnons, spin excitations, and phonons. Polarized neutron scattering is therefore particularly powerful for studying complex magnetic structures, magnetic excitations, and spin–lattice coupling.

We also actively develop and conduct neutron scattering experiments involving strain. Owing to their strong penetrating power, neutrons enable the investigation of lattice and magnetic responses deep within materials under external stress, temperature variations, or across structural and magnetic phase transitions.